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Accessing external I2C EEPROM with Cypress EZ-USB dev kit

Sihan Goi

Hi

I'm trying to add an external EEPROM to my Cypress EZ-USB NX2LP-Flex dev kit, and accessing it using the library functions EZUSB_ReadI2C(), EZUSB_WriteI2C() and EZUSB_WaitForEEPROMWrite().

I plugged in a new 2Kbit EEPROM in the DIP socket and thought it was the only EEPROM there, and I tried reading it at address 0xA0, and was able to get all 0xFFs. I tried to write a single byte to the EEPROM with the following code:

   BYTE xdata temp1;
   BYTE xdata temp2[8];
   BOOL wrOK = FALSE;
   temp1 = 0x01;
   while (!wrOK)
      wrOK = EZUSB_WriteI2C(0xA0,0x01, &temp1);


I then read to read 8 bytes back with the following code

   EZUSB_ReadI2C(0xA0,0x08, &temp2);


Instead of getting all 0xFF except for the 1st byte, I got all 0x01.

I then realized that there are more than 1 I2C EEPROM connected to the SDA/SCL lines, so I'm wondering how do I address the correct one? And once I do that, how do I specify the memory address within the chip? I know the device address for all EEPROM starts with 1010(0xA), but I'm confused as to the later 4bits.

Thanks.

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